In general, power diodes are known that can be implanted as a DC/AC converter for a high voltage resistant and low current driving device. However, such power diodes have a problem in that it is difficult to use in a converter for a high current due to low efficiency and latch-up occurrence. Nonetheless, such power diodes have been applied to various purposes such as an electrostatic protection devices.
It is desirable for a power diode to exhibit a high breakdown voltage. The power diode may include a P-type substrate, an anode and a cathode. In order to increase the breakdown voltage, a guard ring structure that surrounds the anode may be required.
In addition, a parasitic current can flow through the P-type substrate when a forward voltage is applied between the cathode and the anode of the power diode. Therefore, it may be required to suppress the parasitic current to improve the breakdown voltage of the power diode.